Generally, the embodiments of the present invention relate to a method by which a valve assembly is tightly and easily integrated into a gas lighter body made from a non-crystalline resin such as styrene acrylonitrile (AS/SAN) resin, ABS, polycarbonate (PC) and the like. Specifically, the embodiments of the present invention relate to a method of integrating a valve assembly into a lighter body or well therein as a free floating entity not fixed to the lighter body, a well therein, or another component which is itself fixed to the lighter body or a well therein.
Inexpensive gas lighters are typically made of amorphous polymers which have the advantage of transparency such that users are able to see the level of fuel remaining within the lighter's reservoir. Despite this advantage, typically used polymers such as AS/SAN, ABS, and polycarbonate may be brittle as a result of their non-crystalline structure. Additionally, to prevent gas leaks, valve assemblies must be integrated into lighter bodies tightly and with precision. This is often accomplished by press or interference fitting the valve assembly within the lighter body. The stress of this interference fit is often too much for the non-crystalline resin and results in cracking of the lighter body and the necessary disposal of the lighter body.
To avoid this costly issue, several methods have emerged to facilitate integration of valve assemblies without compromising the integrity of the lighter body. One such method, as disclosed in WO 01/18452 A1 and U.S. Pat. No. 4,101,262, employs the use of screw threads and an o-ring such that the valve assembly is screwed upon its thread into the lighter body or a well therein. However, the use of screw threads elongates the manufacturing process as complex moulds are necessary to form the component's threads. Similarly, the introduction of threads complicates the assembly process as it is often difficult to automate the act of screwing the component into the lighter body or well therein. While possibly minimizing the chance of cracking upon the valve assembly's insertion, the use of screw threads is costly in terms of manufacture and assembly.
Additional alternatives include the introduction of a snap-fitting mechanism in which the bottom most part of a valve assembly is formed with a “bulging pawl” that is larger than the well in which the assembly is fit such as disclosed in Japanese patent application JP 7-055140. Upon insertion, the wider “bulging pawl” is compressed such that it snaps into place under the lip of the well at the top of the lighter reservoir. This snapping, in turn, holds the valve assembly in place but does not eliminate the possibility of cracking as the assembly must be inserted with sufficient force to snap the wider section of the assembly (the “bulging pawl”) into place.
Finally, attempts have been made to avoid cracking of a lighter body's resin by the use of an o-ring, press fitting, and annular projections that are ultrasonically welded to the lighter body or a well therein as disclosed in patent WO 2007/140048 A2. That is, the valve assembly itself is formed with projections on its periphery that are melted into the lighter body or a well therein ultrasonically. The disadvantage of this method, however, is the risk of damaging the lighter's permeable membrane by the vibrations produced during ultrasonic welding. Such damage to the permeable membrane may affect the quantity of fuel supplied by the valve assembly and, subsequently, may result in dangerous flame height and fuel leakage during use.